This invention relates to a television receiver capable of simultaneously displaying a plurality of video information on the display screen of a single cathode-ray tube (abbreviated hereinafter as a CRT), and relates also to a method of displaying such video information.
Sources of inputs to a television receiver include not only ordinary television broadcasting stations but also a variety of other sources such as a satellite broadcasting station, a teletext broadcasting station, a CAPTAIN (character and pattern telephone access information network) system, a computer display and a VCR (a video cassette recorder), and the television receiver is demanded to display such many signals. These signals may contain video information interrelated with each other, and it may be preferable to simultaneously display those video information on the single CRT display of the television receiver. For example, a television viewer may desire to see characters of teletext broadcasting in addition to a picture being televised or may desire to simultaneously see different pictures on the same display screen of the television receiver. Thus, when the viewer seeing, for example, sports program desires to read a news program at the same time, it is necessary to simultaneously display characters of teletext broadcasting on the same display screen of the television receiver. In such a case, a method of superimposing the characters on the televised picture according to a so-called picture-in-picture mode or a method of cutting out a part of the televised picture and inserting the characters in that part of the display screen is commonly employed.
However, the methods described above are defective in that a part of the picture is lost due to insertion of the characters, and the entire picture cannot be completely reproduced.